Re: [PATCH v2] firmware/dmi_scan: generalize for use by other archs

[Grant Likely]

On Wed, 27 Nov 2013 15:08:47 +0100, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
> This patch makes a couple of changes to the SMBIOS/DMI scanning
> code so it can be used on other archs (such as ARM and arm64):
> (a) wrap the calls to ioremap()/iounmap(), this allows the use of a
>     flavor of ioremap() more suitable for random unaligned access;
> (b) allow the non-EFI fallback probe into hardcoded physical address
>     0xF0000 to be disabled.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>

Acked-by: Grant Likely <grant.likely@xxxxxxxxxx>

> ---
> 
> Changes since v1:
> - followed Grant's suggestion to use a Kconfig symbol in conjunction with
>   IS_ENABLED() rather than a plain #ifdef to en-/disable the dmi scan fallback
> 
>  arch/ia64/Kconfig           |  1 +
>  arch/ia64/include/asm/dmi.h |  8 +++++---
>  arch/x86/Kconfig            |  1 +
>  arch/x86/include/asm/dmi.h  |  6 ++++--
>  drivers/firmware/Kconfig    |  3 +++
>  drivers/firmware/dmi_scan.c | 20 ++++++++++----------
>  6 files changed, 24 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
> index 4e4119b..bdb4aed 100644
> --- a/arch/ia64/Kconfig
> +++ b/arch/ia64/Kconfig
> @@ -104,6 +104,7 @@ config HAVE_SETUP_PER_CPU_AREA
>  config DMI
>  	bool
>  	default y
> +	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
>  
>  config EFI
>  	bool
> diff --git a/arch/ia64/include/asm/dmi.h b/arch/ia64/include/asm/dmi.h
> index 185d3d1..f365a61 100644
> --- a/arch/ia64/include/asm/dmi.h
> +++ b/arch/ia64/include/asm/dmi.h
> @@ -5,8 +5,10 @@
>  #include <asm/io.h>
>  
>  /* Use normal IO mappings for DMI */
> -#define dmi_ioremap ioremap
> -#define dmi_iounmap(x,l) iounmap(x)
> -#define dmi_alloc(l) kzalloc(l, GFP_ATOMIC)
> +#define dmi_early_remap		ioremap
> +#define dmi_early_unmap(x, l)	iounmap(x)
> +#define dmi_remap		ioremap
> +#define dmi_unmap		iounmap
> +#define dmi_alloc(l)		kzalloc(l, GFP_ATOMIC)
>  
>  #endif
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index e903c71..6350ab4 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -745,6 +745,7 @@ config APB_TIMER
>  # The code disables itself when not needed.
>  config DMI
>  	default y
> +	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
>  	bool "Enable DMI scanning" if EXPERT
>  	---help---
>  	  Enabled scanning of DMI to identify machine quirks. Say Y
> diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h
> index fd8f9e2..535192f 100644
> --- a/arch/x86/include/asm/dmi.h
> +++ b/arch/x86/include/asm/dmi.h
> @@ -13,7 +13,9 @@ static __always_inline __init void *dmi_alloc(unsigned len)
>  }
>  
>  /* Use early IO mappings for DMI because it's initialized early */
> -#define dmi_ioremap early_ioremap
> -#define dmi_iounmap early_iounmap
> +#define dmi_early_remap		early_ioremap
> +#define dmi_early_unmap		early_iounmap
> +#define dmi_remap		ioremap
> +#define dmi_unmap		iounmap
>  
>  #endif /* _ASM_X86_DMI_H */
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index 0747872..5a29fac 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -108,6 +108,9 @@ config DMI_SYSFS
>  	  under /sys/firmware/dmi when this option is enabled and
>  	  loaded.
>  
> +config DMI_SCAN_MACHINE_NON_EFI_FALLBACK
> +	bool
> +
>  config ISCSI_IBFT_FIND
>  	bool "iSCSI Boot Firmware Table Attributes"
>  	depends on X86
> diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> index c7e81ff..17afc51 100644
> --- a/drivers/firmware/dmi_scan.c
> +++ b/drivers/firmware/dmi_scan.c
> @@ -116,7 +116,7 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
>  {
>  	u8 *buf;
>  
> -	buf = dmi_ioremap(dmi_base, dmi_len);
> +	buf = dmi_early_remap(dmi_base, dmi_len);
>  	if (buf == NULL)
>  		return -1;
>  
> @@ -124,7 +124,7 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
>  
>  	add_device_randomness(buf, dmi_len);
>  
> -	dmi_iounmap(buf, dmi_len);
> +	dmi_early_unmap(buf, dmi_len);
>  	return 0;
>  }
>  
> @@ -527,18 +527,18 @@ void __init dmi_scan_machine(void)
>  		 * needed during early boot.  This also means we can
>  		 * iounmap the space when we're done with it.
>  		 */
> -		p = dmi_ioremap(efi.smbios, 32);
> +		p = dmi_early_remap(efi.smbios, 32);
>  		if (p == NULL)
>  			goto error;
>  		memcpy_fromio(buf, p, 32);
> -		dmi_iounmap(p, 32);
> +		dmi_early_unmap(p, 32);
>  
>  		if (!dmi_present(buf)) {
>  			dmi_available = 1;
>  			goto out;
>  		}
> -	} else {
> -		p = dmi_ioremap(0xF0000, 0x10000);
> +	} else if (IS_ENABLED(CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK)) {
> +		p = dmi_early_remap(0xF0000, 0x10000);
>  		if (p == NULL)
>  			goto error;
>  
> @@ -554,12 +554,12 @@ void __init dmi_scan_machine(void)
>  			memcpy_fromio(buf + 16, q, 16);
>  			if (!dmi_present(buf)) {
>  				dmi_available = 1;
> -				dmi_iounmap(p, 0x10000);
> +				dmi_early_unmap(p, 0x10000);
>  				goto out;
>  			}
>  			memcpy(buf, buf + 16, 16);
>  		}
> -		dmi_iounmap(p, 0x10000);
> +		dmi_early_unmap(p, 0x10000);
>  	}
>   error:
>  	pr_info("DMI not present or invalid.\n");
> @@ -831,13 +831,13 @@ int dmi_walk(void (*decode)(const struct dmi_header *, void *),
>  	if (!dmi_available)
>  		return -1;
>  
> -	buf = ioremap(dmi_base, dmi_len);
> +	buf = dmi_remap(dmi_base, dmi_len);
>  	if (buf == NULL)
>  		return -1;
>  
>  	dmi_table(buf, dmi_len, dmi_num, decode, private_data);
>  
> -	iounmap(buf);
> +	dmi_unmap(buf);
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(dmi_walk);
> -- 
> 1.8.3.2
> 

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